I think the entire armor sections needs to be redone and added to rather then a copy paste of old DH armor list. Not just more armor but armor with unique rules.
For starters primative armor needs to go down by 1 on average. Feudal plate is 5 points, heavy yes but its better then a guardsmens flak armor in the new rules. You make them comparable. Feudal 4, chain 2 with leather staying 1. Have a mono style upgrade that makes it less primitive so a feudal suit made of plasteel is now ap 5 and is sort of ceremonial carapace armor while chain main of thermoplas becomes bulky mesh armor.
Helmets should be standardized to the set. Either -1 ap of whatever suit they fit. If you make flak helmet ap 2 but the set is 3 and guard flak helm somehow gets ap 4. That or make it equal protection to the suited. It feels extremely out of place to have only suits get good helmets.
Perhaps expanding the various armor types out and throwing in a few more exotic bits. I know you can easily add whatever as GM but having a more solid base is always nice.
Have a few more subtle armor types a nondescript flakweave cowl/hood is ap 2 but a ap 3 flak helm or 4 guard flak helm attracts attention. Mesh is covert but only 3 ap.
More examples of industrial armor. Protective work helmets that allow you to blend in on a hive/forge world but have poor field of view and muffled hearing -10 awareness but +10 bright flash or loud noises. A slaughtermans chain vest for butchering AP 3 but on the front of the body and legs only.
As well some types of other indigenous armor to the sector. Perhaps leg guards used to ride glass steeds. Mechanicus Arma glass masks for exploring vacuum or airless environments. bulky Forge suits that protect against high temperature and fire damage. A lot of flavor here.
More in depth rules for customizing of armor. Weapons get an amazing spectrum of upgrades and there are so many to choose and use. Lot to work with here. You can have ablative armor that gives 2 points to a section but each attack removes a point and then has to be replaced. chem injectors which can be triggered remotely or when damaged. To specific armor type upgrades such as carapace, feudal plate and power armor can have hexagrammic wards to allow some protection to psychic attacks. Flak riot padding gives +1 ap to attacks from primitive weapons and Mesh armor insulation +1 ap to Energy attacks.
More armor that has special rules as well. Perhaps the bodyglove gets a +5/10 to dodge if worn with no other armor. The effect being both of padding if you take a dive and the flexibility and ease of movement as if you were wearing nothing at all.
The section just seemed one of the weakest points of the beta and of the original DH. You had an entire galaxy of interesting weapons, tools, drugs and cybernetics but the armor was sort of an afterthought getting a single page.